1. Field of the Invention
The invention relates generally to the design and construction of electrical connections for use in sondes and other wellbore logging tools. In particular aspects, the invention provides devices and methods for improved packaging of electrically conductive elements within such a tool and for protecting said elements against wellbore fluids.
2. Description of the Related Art
A number of tools are known today for logging or sensing conditions within a wellbore during various portions of the well productions process. These sensing tools, or sondes, include an outer casing or sub that is often disposed into a wellbore on wireline. Alternatively, the sub may be disposed into the wellbore on coiled tubing or as part of the drill string or even production tubing. The sensing tools are capable of detecting a wide variety of downhole conditions, including temperature, pressure, porosity, resistivity, and so forth. The sensing tool generally features a sensor disposed on the outer side surface of the sub or embedded therewithin the side surface. Electronic equipment is disposed within the interior of the sub, and is typically contained within compartments behind sealed bulkheads that are located proximate each axial end of the sub. This electronic equipment typically includes processing circuitry, storage media, and power sources.
Fluid sealing is provided around the sensor to prevent entry of fluid into the interior of the sub. If damaged, however, the seal may permit fluid to flow into the interior of the sub. A typical external environment for a sonde would be one where the wellbore fluid is at a pressure state that higher than the interior of the sub. The pressure difference may range from 50 psi to 30,000 psi. Once inside the sub, the fluid may corrode or otherwise destroy the conductivity of the wiring that extends between the sensor and the components housed within the two axially-located chambers. Additionally, if either of the bulkheads are breached, the intruding fluid might easily destroy the electronic components housed within. Additionally, present techniques for constructing sondes with bulkheads and the necessary bulkhead electrical connectors are time consuming and costly.
The present invention addresses the problems of the prior art.